GE PLC Communication Protocols

General Electric has long made PLCs and other control devices for automation systems. These devices have had a reputation for being reliable and have been used in control design projects worldwide. For most of that time, GE PLCs were marketed under the name GE Intelligent Platform and Alstom Power Automation as part of the General Electric Automation and Control segment of GE’s business portfolio. Emerson Electric acquired GE Intelligent Platforms (also known as GE Fanuc) in 2019 and renamed the company Machine Automated Solutions.

GE Proprietary Communication Protocols

Many PLC manufacturers have proprietary protocols.  Others can operate over a range of standard protocols allowing ease of interoperability among a variety of vendors.  GE developed such proprietary protocols, and they remain in use with their current and legacy PLCs today.  

• CCM – CCM stands for Coprocessing Communication Module and is the communication protocol designed by GE for its series 6 line of PLCs. The protocol remained in use through the Fanuc 90/30 and 90/70 series. It could be used on EtherNet networks using a gateway controller.
• SNP – Beginning with the Fanuc series 90 families of 90/30 and 90/70, GE developed the more advanced Series Ninety Protocol (SNP). This communication protocol allows any series 90 PLC to communicate with another series 90 or with other devices in the system over a serial line. SNP is half-duplex and uses both RS-485 and RS-232. SNP facilitates communication between server PLCs and client PLCs and devices within a system. It may be deployed as either a point-to-point or multidrop network.
• SNPX – The SNPX communication protocol has the same capabilities as the SNP. However, it can only communicate with series 90/30 over serial lines and not with other 90 series family members such as the 90/70. An additional difference between the SNP and SNPX is that the SNPX is significantly faster than the SNP over point-to-point lines by a factor of 10%.  In multidrop configurations, SNPX is up to 10 times faster than SNP
• SRTP – GE Fanuc developed Service Request Transfer Protocol for most PLCs in their line that uses an EtherNet port. This protocol works with a fieldserver allowing the PLC to act as a client. It will enable the PLC to write to system memory or create responses to read requests.  
• Genius – Genius was developed as a mode of communication across GE PLCs of different series. It utilized the Genius Bus and allowed seamless communication between GE controllers of various types.

Additional Communication Protocols by Series

Generally, GE communications protocols are as follows:

• Series 6 – CCM
• Series 90/30 – SNP and SNPX
• Series 70 – SNP

The Genius line of products has now been retired, but the interface for communication between GE PLCs using Genius bus and protocol is:

• Series 90/30 PLC
• Series 90/70 PLC
• Series 6 and 6 Plus
• Series 5

As do most OEMs, each series can also use other industry protocols, either embedded or as add-on modules.  Here is a look at additional communication protocols by family series:

• 6 Series – The GE 6, 60, and 600 series PLCs came to market in the 1980s and are now considered legacy PLCs. While they are no longer manufactured and supported, they are still available in refurbished condition. The 6 series utilized the CCM protocol to connect devices via a serial interface connected to point-to-point, multidrop, or Genius systems. Depending on the distance of the cable run, the CCM modules could connect to several serial communication protocols via two serial ports, including:

• RS-232 for short distances of up to 50 feet
• RS-422 for longer runs of up to 4000 feet.
• GE Durus Compact PLC – Like most controller OEMs, GE also offers the Durus compact controller. The Durus is a compact and ruggedly designed controller usually deployed at the machine level and in standalone applications. 

The Durus compact PLC by GE was designed for applications that require less than 44 analog I/Os. It is used in demanding environments to replace traditional clocks and timers in applications requiring more precise control. Communication protocols supported by the Durus line include:

• Modbus – Client
• Profibus – Client
• DeviceNet – Client
• EtherNet – Server.

• VersaMax PLC – The VersaMax PLC was designed for streamlined use in moderately demanding applications. It is a low-profile device that can be added to PLC control systems alongside other GE PLCs, such as the 90/30 series. 

Designed for both standalone and integrated use, VersaMax family members may be micro or nano. They are available across both AC and DC as well as analog and digital. The VersaMax is flexible for localized use but has limited communication capabilities compared to other models. Communication protocols supported by the VersaMax PLC include:

• Genius
• Profibus-DP
• DeviceNet

• GE Fanuc Series 90/30 – The 90/30 series was designed for flexibility and a wide range of I/O configurations. By combining I/O modules, CPUs, and other specialty modules, control system designers could customize and scale a control system to meet complex applications and demanding environments.  

The 90/30 controller series could be configured over LAN and used in multidrop situations using Ladder Logic. With this flexibility, the 90/30 series can handle simple applications with as low as 32 I/Os up to 4000 I/Os for more complex environments.

The 90/30 series was designed to use GE’s Genius Bus product to tie the 90/30 to other GE products such as the 90/70 series and other devices. This meant that communication between those devices was automatic. The Genius modules are no longer sold or supported by GE (Emerson).

The 90/30 series uses Ethernet TCP/IP. Some communication network protocols are server-only, client-only, or both. These include:

• World FIP – Server and client
• Profibus-DP – Server and Client
• Interbus-S – Client
• LonWorks – Server
• DeviceNet – Server
• SDS – Server
• CAN Open – Server 
• Modbus RTU – Server and Client

The 90/30 series models have between 1 and 3 serial communication ports depending on the model.  Adding a Communication Coprocessor Module will also allow 2 serial ports with built-in protocols for SNP/SNPX (server/client), CCM, and Modbus RTU.

• GE Fanuc Series 90/70 – The 90/70 series PLC was developed to work as part of a modular system to allow scalability and increased power to design systems. It was more redundant than its predecessors. And its modularity also meant more computing power and communication capability were achievable.

The 90/70 series was developed as an open architecture system. This meant enormous scalability of PLCs and other devices across a complex ecosystem for advanced machine control. Using Intel-based processors, these PLCs could tie to other GE products and a wide range of different devices and PLCs from other manufacturers, reducing the system upgrade cost. It accomplished this using the VME-Bus standard so controllers, boards, and other devices could be added and custom configured for the control system’s exact needs.

The 90/70 series uses Ethernet TCP/IP. Because of the 90/70 series’ modularity, modules that enable different communication protocols allow connection to an existing network. Busses used with the 90/70 to enable these protocols include:

• World FIP 
• Profibus-DP 
• Interbus-S 
• LonWorks 
• DeviceNet 
• SDS 
• CAN Open 
• Modbus RTU 

• PACSystems RX3i – The GE RX3i was the workhorse that replaced the 6 series with greater storage options, a broader range of I/O possibilities, and greater modularity. These PLCs could be connected to an Ethernet Global Data Gateway (EGD) to work with other OEM control system components or link to the GE Global Data Network.

The GE Global Data Network protocol was explicitly designed for GE Fanuc PLCs. 

It allows data to be sent across GE PLCs, drives, HMIs, and SCADA systems. The RX3i was designed with redundancy in mind. A valuable feature in industrial automation for safety, quality, and potential wear and tear. The RX3i uses Profinet redundancy for media, network, device, and controller redundancy.

The RX3i also has between 1 and 3 Ethernet ports (depending on the model) that allow a wide range of Ethernet protocols. These include:

• SRTP Client/Server
• Modbus TCP/IP
• OPC-UA Server
• EGD
• Profinet
• DNP Outstation
• IEC-61850 Client
• IEC-104 Server
• HART Passthrough

The IEC-104 Server, IEC-61850 Client, and the DNP Outstation can only be accessed via an additional module.

The RX3i also uses the ASCII Serial and Modbus/RTU as serial protocols on all models except the IC695CPE400 and IC695CPL410, which uses ASCII Serial as its only serial communication protocol. The Modbus/RTU serial protocol is also only available as an add-on module. All RX3i models except the IC695CPE330 allow interfacing through RS-232. And the IC695CPE310 allows both RS-232 and RS-485.

Tags: Communication Protocols, GE PLC, GE PLC Communication

This entry was posted on March 19th, 2021 and is filed under Automation, Communication, GE Fanuc. Both comments and pings are currently closed.